Ubuntu Wiki

• Launchpad Entry: installer-for-windows

• Created: 2007-04-26

• Contributors: HenrikOmma

• Packages affected:

Note: spec revamped for Feisty. Related specs exist in the wiki and LP for specific technical solutions. Please keep this spec neutral until a technical approach has been selected.

Summary

A simple install procedure for Ubuntu initiated in Windows.

Rationale

Windows users are often more comfortable with downloading a small ubuntu.setup.exe file than downloading and burning an ISO. Some laptops do not have a CD drive and many systems are configured to boot from the HD first.

Use Cases

Scope

Select the most suitable technical solution.

Design

TODO: Select from one of several possible technical solutions.

Windows installers for Ubuntu

Several Windows-based installers for Linux (including Ubuntu) have appeared recently, each using different methods. The common goal of these is to provide a simple path to Ubuntu that starts with downloading a small executable installer, and removes the need to use a CD. The three main approaches are:

1. Repartition and install

   • downloads packages or ISO
   • an entry in the Windows bootloader is created
   • reboot to start an installer (text-based, graphical or Live CD based) asking the usual questions
   • The disk is resized or free space is used (ie. normal install)
   • GRUB is installed
   • Boot again to start Ubuntu
   • Next time you start Windows the entry from the Windows bootloader

   • Implementation: [http://goodbye-microsoft.com/ win32-loader], [http://instlux.sourceforge.net/ instlux], [http://ubuntuforums.org/showthread.php?t=427793 Wubi-netboot]

2. Install on a loop mounted disk image

   • downloads packages or ISO
   • Gathers information from Windows and simply asks for a user name and password
   • Adds Ubuntu entry to the Windows bootloader
   • Reboots to start an install process (non-interactive)
   • Reboot again to start Ubuntu (or Windows)
   • Painless removal of Ubuntu of desired

   • Implementations: [http://www.cutlersoftware.com/ubuntusetup/wubi/en-US/index.html Wubi]

3. Install a virtual machine

   • Installer contains a copy of Virtualbox and downloads a pre-made virtual machine of Ubuntu
   • Simple NSIS install and launch VM directly without reboot
   • Simple unistall
   • Has to share resources so performance will be reduced and hardware support may be limited

   • Implementations: [http://www.virtualbox.org/ Virtualbox], [http://www.h7.dion.ne.jp/~qemu-win/ QUEMU]

An overview of existing implementations follows.

win32-loader

Summary: Download a small executable which downloads the netboot files, modifies the NT bootloader and reboots.

Links: http://goodbye-microsoft.com/

Advantages

• Fast download in first installer stage (netboot stuff only)
• A real ubuntu install on a real partition

Disadvantages

• Mistakenly grabbed the 64-bit version on a 32-bit virtual system and failed to boot (admittedly an odd test case)
• Leaves the bootloader behind
• No accessibility support in alternate installer
• Does not work with Vista

instlux

Summary: same principle as win32-loader, but a slightly cleaner implementation usability-wise.

Advantages

• Fast download in first installer stage (netboot versions)
• A real ubuntu install on a real partition
• Cleans up the NT bootloader after install

Disadvantages

• Text-based install (could use graphical d-i)
• No accessibility support in alternate installer
• Does not work with Vista
• Does not work on Win9x
• Only currently supports Ubuntu 6.06 and older

Wubi-netboot

Summary: A stripped-down version of Wubi which allows for installation to a real partition without a CD using the netboot installer, but lacks the ability to autodetect Windows settings or install on a loopmounted partition. Wubi-netboot is a temporary fork of Wubi which will be discontinued once Wubi implements support for installation on a real partition.

Advantages

• Currently works with Ubuntu 7.04, 6.10, and 6.06.1 LTS
• No download needed in first installer stage (initrd and kernel come bundled in 7.3 - 8.5 MB package)
• A real ubuntu install on a real partition
• Cleans up the NT or Win9x bootloader after install

Disadvantages

• Text-based install (could use graphical d-i)
• No accessibility support in netboot installer
• Does not work with Vista

Wubi

Summary: An Ubuntu community project the Windows Ubuntu Installer uses method 2, a loop mounted disk. Download a simple .exe file which launches an NSIS installer. It asks for your user name and password and reboots to install. Ubuntu is actually installed on a loop-mounted drive stored as an image file within the Windows file system. Previously known as 'install.exe' in the wiki. The back-end relies upon debian-installer with preseed. The preseed file is generated by the Windows front-end. The only modifications to a stock d-i mechanism are those required to support loop-installation mode, see [http://launchpad.net/lupin lupin] for technical details. Current development is taking place within the [http://launchpad.net/lupin lupin] (back-end) and [http://launchpad.net/wubi wubi] (front-end) projects hosted on Launchpad.

Links: [http://www.cutlersoftware.com/ubuntusetup website], [http://ubuntuforums.org/forumdisplay.php?f=234 forum], [https://wiki.ubuntu.com/install.exe wiki], [http://launchpad.net/lupin lupin], [http://launchpad.net/wubi wubi]

http://www.cutlersoftware.com/ubuntusetup/wubi/en-US/screenshots/wubi3.jpg

Advantages

• No disk resizing or partitioning required
• No CD burning required
• Easy to remove Ubuntu from the system, restoring the system to its previous state
• The bootloader is not replaced, an additional boot option is addded to it
• Runs at native speeds using all system resources (provided the loop mounting is efficient)
• Installer/uninstaller behaves as an ordinary application installer/uninstaller, which is comfortable for the user
• Installed system behaves as an official Ubuntu dual-boot installation (the only modifications are required to boot from a loopfile, reboot cleanly and upgrade the kernel, but a regular user would not spot the difference).
• Virtual disk image can potentially be migrated to a real partition in a second moment, offering a clean upgrade path once Ubuntu has won user goodwill. Note: a migration tool has not yet been developed.
• Simplyfied installer: asks very few questions during installation as it gathers required information from a working OS. The installer supports migration-assistant and download resume. The same installer works with any Ubuntu (and Debian) flavours that provide an alternate ISO.
• Clean separation of front-end and back-end, allows to port the installer to different platforms by only changing the front-end.
• Being based on d-i, all features supported by d-i are available, therefore installation to a real partition can also be implemented as an option.

• The back-end mostly consists of a patched initramfs and a dynamic ISO patching mechanism to add loop-installation support, and its functionalities could be added to the official initrd/installer. A blueprint (https://blueprints.launchpad.net/ubuntu/+spec/lupin) has been proposed to merge such functionalities within Ubuntu.

Comparison to other methods

• Unlike a LiveCD, and taking advantage of its uninstallation capabilities, Wubi offers an install-then-try approach as opposed to a try-then-install approach.
• Unlike a LiveCD/Virtualmachines there is no distinction between "demo" mode and "real" mode.
• Unlike Virtualmachines there is no need for the host OS to be running and the user can concentrate on the new OS.
• Unlike Virtualmachines there is full hardware access and no performance degradation (other than disk I/O)
• Unlike Netboot methods, installation files (sourced from the alternate ISO) are pre-downloaded by the front-end within Windows, avoiding potential networking issues which might affect netboot methods which rely on Linux networking
• Unlike Netboot methods, it works in offline mode, by placing the installer and the ISO file within the same folder.
• Unlike Netboot/Traditional installation methods, the system can be installed without requiring operations perceived as "dangerous" by the user such as repartitioning and bootloader replacement.
• Unlike Netboot/Traditional installation methods, the installation can be removed cleanly, restoring the system to its previous state.
• It is possible to move the loop-files to dedicated partition in a later moment without forcing that decision on the user on day 1

Disadvantages

• Does not yet work with Vista
• Uses alternate disc to install from, that said, the ISO is used only in the background as a source of packages, the only difference from netboot methods is that by pre-downloading the ISO, all packages are available in one go without having to rely on Linux networking
• Fixed size disc image: virtual disk size will be selectable from the installer, and an extra virtual disk can be added, but it would be nice to have a dynamic image or manual resize option
• Requires write access to the host file system, which in the case of windows requires installation of ntfs-3g
• Windows fragmentation can impact disk I/O performance of Ubuntu.
• It uses grldr (grub for windows), which is less reliable than a standard grub bootloader. For instance, grldr fails when the initrd/kernel is fragmented.
• On FAT filesystems the file size limit of 4GB applies to the virtual disks.

Work oustanding

• Needs a dash of usplash in a few places
• Needs a graphical installer front-end to d-i, even though once d-i gtk frontend is included in the alternate ISO that can be used for progress bars
• Better post-install management features. A control panel running in windows that lets you resize discs, make backups, select between different installed systems.

Outsanding questions

• How efficient is the loop mounted drive?
• How easy would it be to move such an install out from under windows to a separate partition (perhaps an improved version of the migration tool could be used?)

Virtual Box

Summary: The GPL version of Virtualbox can be packaged and distributed on the net and on 3rd party CDs.

Link: http://www.virtualbox.org/

Advantages

• Simple install with no need to reboot
• Simple unistall
• Dynamic disk images that lets users install and explore more software
• Runs in parallel with the Windows session, allowing you to switch back and forth
• Several distro flavours can be installed simultaneously
• Runs under Vista

Disadvantages

• Poor peformance
• Driver problems, no support for Beryl/Compiz
• GPL version lacks some features like USB support
• Host OS is needed, which makes the user less focused on the new OS

Implementation

Depends on the design choice.

Outstanding Issues

Pick a design.

BoF agenda and discussion

Discuss at UDS Seville.

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